Since the beginning of this century, the total amount of energy consumed in the United States for all forms of transportation has been taking an increasing percentage of the total annual energy production. In 1970, for example, transportation consumed approximately 25% of the total energy produced for that year. If the present trends continue, transportation energy consumption will overtake the total industrial consumption during the early part of the 1980's and will become the single largest consumer of energy. There are two fundamental reasons for these trends: (1) the desire for faster transportation vehicles and (2) an increasing population. For all practical purposes, the amount of energy expended in propelling a vehicle is directly proportional to the square of its operating speed. But the desire for higher transportation speeds appears to take precedence over all other factors -- thus producing and accelerating the high transportation energy consumption.
At first glance, it may appear that these facts rest upon basic physical laws that cannot be circumvented. For example, accelerating a vehicle along an essentially level highway or railway to reach high speeds requires a large amount of energy. This energy is usually totally expended when the vehicle is brought to a stop. However, instead of supplying this energy by large powerful on-board engines, as in conventional ground transportation systems, it is possible to remove them completely and utilize a vast energy resource that nature has placed at out disposal -- namely gravity.
An object of this invention is to provide a gravity powered ground transportation system that is versatile and that will give very high operating speeds with very little energy consumption. This will be achieved by designing the vehicle so that it can move with almost zero friction in vacuum tunnels and therefore capable of converting potential energy into kinetic energy and vice versa through the principle of conservation of energy with almost no perceptible loss.
Before proceeding to a description of the invention it should be noted that gravity power and the process of transforming potential energy into kinetic energy is not new. In fact it is the source of water wheel power and more modern hydroelectric power. However, large machines that regularly transform potential energy into kinetic energy and vice versa have a more recent origin. Moveover, they have tended to emerge as machines of amusement rather than machines for practical work. The roller coaster is an excellent example. Unfortunately, rolling friction and air resistance give them rather low conversion efficiencies. There are many hybrid machines that utilize a combination of energy sources such as heat, potential and kinetic energies.
One interesting machine proposed by Edwards in U.S. Pat. No. 3,605,629, for ground transportation utilized pneumatic atmospheric pressure, potential and kinetic energies. See also his U.S. Pat. No. 3,601,158. The system involved vehicles propelled as a free piston through air tight tubes by a differential air pressure applied between the ends of the vehicle. Although an assist was supplied by gravity, the system was primarily designed around the pneumatic propulsion concept and required a great deal of large pneumatic support equipment such as compressors, valves, vents and very large air locks.
In every prior transit system large amounts of propulsive thrust are applied either within the vehicle, as by motors, or externally by pneumatic, or magnetic forces, or the classic cable cars of San Francisco.
Aside from the relatively inefficient and trivial roller coaster application of the principle of conservation of energy (potential and kinetic representations) there appears to be no previous attempt to utilize this principle as the fundamental propulsion means. The roller coaster quickly "runs down" and is clearly not suitable for a practical rapid transit system. Of course, the reason is quite obvious -- frictionless motion could not be obtained. However, recent technological developments, particularly in the field of magnetic levitation, open the way for actually achieving motion without friction. This invention utilizes these developments to provide a rapid transit system that is based entirely on the principle of conservation of energy.
In my copending U.S. Pat. Application Ser. No. 438,230 entitled RAPID TRANSIT SYSTEM, filed Jan. 31, 1974, I show how an economical magnetically levitated rapid transit system can be designed to operate almost entirely on gravity power. The realization of the system, however, depends upon the attainment of drag-free levitation at high speeds. In the above mentioned patent application the suspension system is based upon ferromagnetic attraction using servo-controlled electromagnets assisted by superconducting magnets of constant field strength. Although this system can indeed provide very high lift to drag ratios if the ferromagnetic suspension and guide rails have high resistivity and are laminated, there are nevertheless some non-negligible drag that causes power losses which increase at higher speeds.
The rapid transit system disclosed in this application differs from the former in that the levitation system has zero magnetic drag at all speeds and does not consume energy. This is accomplished by utilizing magnetic forces of repulsion between like poles of permanent magnets. Thus, for example, by laying rails composed of permanent magnets with north poles facing up, a train fitted with other permanent magnets directly above the rails with north poles facing down, can be suspended by the resulting magnetic repulsion forces (see Polgreen's article, "Rail-Ways With a Magnetic Suspension," The Engineer, Oct. 25, 1968, pp. 632-636). Moreover, such a levitation system not only gives zero magnetic drag, but also requires zero energy to maintain this levitation. Hence, energy from on-board energy storage units that would otherwise be needed for vehicle levitation can be used to provide additional major vehicle propulsion that could be recovered by regenerative braking. An object of this invention is to provide an economical gravity/flywheel powered rapid transit system utilizing drag-free static repulsive fields of permanent magnets with high coercivity.